Reaction products and methods for making and using the same

ABSTRACT

Reaction products and methods for making and using the same are provided. The reaction products particularly may include adducts of two or more reactants. The adducts particularly can incorporate a nitrification inhibitor, such as DCD. In particular embodiments, reaction products may be formed from the reaction of formaldehyde, DCD, urea, and an ammonia source. The adducts may be included in agricultural products, including fertilizer compositions and nitrification inhibitor systems. Fertilizer compositions including the adducts can be beneficial for reducing leaching of nitrification inhibitors applied to soil.

CROSS-REFERENCES TO RELATED APPLICATIONS

The present application is a continuation-in-part of U.S. patentapplication Ser. No. 13/098,272, filed Apr. 29, 2011, and claimspriority to U.S. Provisional Patent Application No. 61/329,680, filedApr. 30, 2010, the disclosures of which are incorporated by referenceherein.

BACKGROUND OF THE INVENTION

Embodiments described herein generally relate to fertilizers. Moreparticularly, such embodiments relate to reaction products that providean extended period of nitrification inhibition and methods for makingand using the same.

Fertilizers typically include urea, ammonia, ammonium nitrate, or amixture thereof to provide a source of nitrogen. Nitrogen is a vitalnutrient for plant growth. When urea is used as a source of nitrogen inthe fertilizer, the urea converts to ammonia as a result of hydrolysiscatalyzed by urease, which is an enzyme produced by numerous fungi andbacteria found in the soil. Ammonia rapidly undergoes ionization in thesoil to form ammonium. In most soils, the resulting ammonium and theammonium nitrate, if present, are readily oxidized to nitrate (NO₃) viaa sequence of bacterial oxidation reactions, which is commonly referredto as “nitrification.” Nitrification of the ammonium, however, happensso fast that a large percentage of the nitrogen in the fertilizer islost before the plants can utilize it.

Nitrogen is also lost from the soil through volatilization to theatmosphere. Nitrate, another source of nitrogen, is typically lostthrough leaching into the subsoil by rainwater and/or throughdenitrification, i.e., bacterial conversion of nitrate to elementalnitrogen.

Attempts to reduce such losses of nitrogen have utilized ureaseinhibitors and/or nitrification inhibitors as additives to thefertilizer. Urease inhibitors are compounds capable of inhibiting thecatalytic activity of the urease enzyme on urea in the soil.Nitrification inhibitors are compounds capable of inhibiting thebacterial oxidation of ammonium to nitrate in the soil. Nitrificationinhibitors, however, tend to leach into the soil, away from the plant,thus becoming ineffective at inhibiting nitrification where it isneeded—near the plant.

There is a need, therefore, for improved fertilizers that provide anextended period of nitrification inhibition and methods for making andusing the same. There is also a need for improved products that reducenitrification in soil and methods for making and using the same.

SUMMARY OF THE INVENTION

The present disclosure provides compositions that are useful inagricultural applications. The compositions can be nitrificationinhibitor compositions and/or fertilizer compositions. The compositionscan include one or more adducts arising from a reaction of a pluralityof materials. In some embodiments, the compositions can include one ormore adducts arising from a reaction of formaldehyde, DCD, urea, and anammonia source. For example, the present compositions can include one ormore triazonyl-formaldehyde-DCD adducts, urea-formaldehyde-DCD adducts,DCD-formaldehyde-oligomer adducts, and/or urea-formaldehyde-oligomeradducts. The compositions can be particularly useful for inhibitingnitrification of a nitrogen source in soil.

In some embodiments, the present disclosure may relate to anagricultural composition. Such agricultural composition may, forexample, comprise a material selected from the group consisting of urea,DCD, urea-formaldehyde polymer (UFP), ammonia, and combinations thereof,and may further comprise at least one adduct according to the structureof Formula 4

wherein: X is O or

R₁, R₂, R₃, and R₄ are independently selected from the group consistingof:

andwherein, if X═O, at least one of R₁, R₂, R₃, and R₄ is

In some embodiments, a composition according to the present disclosuremay specifically include at least one adduct according to the structureof Formula 5, Formula 6, or Formula 7,

In some embodiments, an adduct (for example, an adduct according to thestructure of Formula 5, Formula 6, or Formula 7) can be present in acomposition at a concentration of about 0.1 to about 10 wt. % based onthe total weight of the composition. In certain embodiments, each of theadducts according to Formula 5, Formula 6, and Formula 7 can be presentin the composition.

In some embodiments, a composition including an adduct as describedherein may be in the form of an aqueous mixture. In particular, suchaqueous mixture may have a pH of 7 or greater. In particularembodiments, the aqueous mixture can comprise2-cyano-1-((4-oxo-1,3,5-triazinan-1-yl)methyl)guanidine,1-((2-cyanogauanidino)methyl)urea,2-cyano-1-((2-cyanoguanidino)methyl)guanidine, and DCD. Optionally, theaqueous mixture further can comprise urea. Also optionally, the aqueousmixture further can comprise ammonia.

In some embodiments, the present disclosure may relate to anitrification inhibitor system. Such system may, for example, comprise amixture of a triazonyl-formaldehyde-DCD adduct, a urea-formaldehyde-DCDadduct, and a DCD-formaldehyde-oligomer adduct. In further embodiments,the nitrification inhibitor system can comprise about 0.1 to 10 wt. % ofthe triazonyl-formaldehyde-DCD adduct based upon the weight of thenitrification inhibitor system and/or the nitrification inhibitor systemcan comprise about 0.1 to 10 wt. % of the urea-formaldehyde-DCD adductbased upon the weight of the nitrification inhibitor system and/or thenitrification inhibitor system can comprise about 0.1 to 10 wt, % of theDCD-formaldehyde-oligomer adduct based upon the weight of thenitrification inhibitor system. In some embodiments, the nitrificationinhibitor system further can comprise water and/or free DCD, inparticular embodiments, the nitrification inhibitor system can compriseone or more adducts selected from2-cyano-1-((4-oxo-1,3,5-triazinan-1-yl)methyl)guanidine,1-((2-cyanoguanidino)methyl)urea, and2-cyano-1-((2-cyanoguanidino)methyl)guanidine

In some embodiments, the present disclosure can relate to a method ofpreparing a nitrification inhibitor system. Such method may comprise,for example, reacting formaldehyde, DCD, urea, and an ammonia source soas to form an aqueous solution comprising an adduct of DCD. Preferably,the reacting can be carried out at a pH of 7 or greater. Further, thereacting can be carried out such that the adduct of DCD comprises one ormore of a triazonyl-adduct, a urea-formaldehyde-DCD adduct, and aDCD-formaldehyde-oligomer adduct.

In some embodiments, the reacting can comprise reacting formaldehydewith at least a portion of the ammonia source to form a first mixture.The reacting further can comprise reacting the first mixture with theDCD to form a second mixture. The reacting further can comprise reactingthe second mixture with urea to form a third mixture. The reacting alsocan comprise reacting the third mixture with a portion of the ammoniasource.

In further embodiments, the present disclosure can provide for reducingnitrification in soil. Such methods can comprise applying anagricultural composition as described herein.

Such methods particularly can comprise applying a composition thatincludes one or more adducts as described herein. In some embodiments,such methods can comprise combining a nitrogen source and thecomposition prior to applying the composition to the soil. In someembodiments, the methods can comprise applying the composition to thesoil in an amount that ranges from about 1 kg/ha to about 50 kg/ha. Insome embodiments, a nitrogen source can be applied to the soil prior toapplying the composition to the soil. In some embodiments, thecomposition can be applied to the soil before a nitrogen source isapplied to the soil.

BRIEF SUMMARY OF THE FIGURES

FIG. 1 is a UV (214 nm) chromatogram showing peaks corresponding todifferent components of a reaction product according to one or moreembodiments of the present disclosure;

FIG. 2 is a printout of a mass spectral analysis of a reaction productaccording to embodiments of the present disclosure confirming thepresence of the adduct of Formula 5; and

FIG. 3 is a printout of a mass spectral analysis of a reaction productaccording to embodiments of the present disclosure confirming thepresence of the adduct of Formula 6.

DETAILED DESCRIPTION OF THE INVENTION

The present disclosure relates to various reaction products, andparticularly relates to products of the reaction of a nitrificationinhibitor with one or more further compounds. Such reaction products maybe characterized as adducts in that the new compounds arising from thereaction retain two or more of the reactants. In particular, adductsincluding the nitrification inhibitor used in the reaction are providedherein. In some embodiments, the present disclosure relates to adductsarising from the reaction of a nitrification inhibitor with urea andformaldehyde. In some embodiments, the reaction products can be includedin admixture with further compounds. The admixture can include one ormore adducts as described herein and a content of one or more of thereactants utilized in forming the adducts. In some embodiments, theadducts can be combined with a fertilizer. As such, the presentdisclosure can provide one or more adducts, compositions comprising oneor more adducts (e.g., aqueous solutions thereof), fertilizercompositions comprising one or more adducts, methods of forming adducts,methods of forming fertilizer compositions comprising one or moreadducts, methods of inhibiting nitrification, and methods of reducingleaching of a nitrification inhibitor applied to soil.

In some embodiments, the present disclosure can provide a reactionproduct of any three or more of the following: formaldehyde, an ammoniasource, a nitrification inhibitor, urea, and a urease inhibitor. Forexample, an adduct provide herein may be a reaction product offormaldehyde, an ammonia source, and a nitrification inhibitor. Asanother non-limiting example, an adduct provided herein may be areaction product of formaldehyde, an ammonia source, a nitrificationinhibitor, and urea. As a further non-limiting example, an adductprovided herein may be a reaction product of formaldehyde, an ammoniasource, a nitrification inhibitor, urea, and a urease inhibitor. As yeta further non-limiting example, an adduct provided herein may be areaction product of formaldehyde, an ammonia source, a nitrificationinhibitor, and a urease inhibitor. As still another non-limitingexample, an adduct provided herein may be a reaction product offormaldehyde, an ammonia source, urea, and a urease inhibitor.

Adducts as described herein may be combined with a variety of furthermaterials to form various compositions. For example, a composition maycomprise one or more adducts described herein in combination with anitrogen source. The combination with a nitrogen source may particularlybe utilized as a fertilizer composition. As a further example, acomposition may comprise one or more adducts as described herein incombination with a urease inhibitor. When combined with a ureaseinhibitor, the adducts may or may not arise from a reaction wherein aurease inhibitor was also a reactant.

The nitrogen source for use in compositions described herein caninclude, but is not limited to, urea, ammonium nitrate, anhydrousammonia, aqueous ammonia, urea-formaldehyde polymers, or any combinationthereof. The nitrogen source can be a solid, liquid, gas, or anycombination thereof. Illustrative solid nitrogen sources can be in theform of pellets, prills, flakes, granules, and the like. Illustrativeliquid nitrogen sources can be aqueous and/or liquid solutions of one ormore nitrogen sources. The nitrogen source can be quick releasenitrogen, controlled release nitrogen, or a combination thereof. As usedherein, the term “quick release nitrogen” refers to free urea, ammoniumnitrate, anhydrous ammonia, aqueous ammonia, or any combination thereof.As used herein, the term “controlled release nitrogen” refers to asubstituted urea, reacted urea, e.g., urea-formaldehyde polymer, or acombination thereof. The term, “controlled release nitrogen” can alsorefer to a nitrogen containing material that coverts more slowly thanurea in soil to plant available nutrients ammonium and nitrate than areference quick release nitrogen source. Another suitable nitrogensource can be or include animal waste(s) such as urine and/or manureproduced by one or more animals, e.g., cows, sheep, chickens, buffalo,turkeys, goats, pigs, horses, and the like.

As used herein, the term “nitrification inhibitor” refers to anycompound(s) that reduces, inhibits, or otherwise slows down theconversion of ammonium (NH₄ ⁺) to nitrate in soil when present ascompared to the conversion of ammonium (NH₄ ⁺) to nitrate in soil whennot present. Illustrative nitrification inhibitors can include, but arenot limited to, 2-chloro-6-trichloromethyl-pyridine,5-ethoxy-3-trichloromethyl-1,2,4-thiadiazol, dicyandiamide,2-amino-4-chloro-6-methyl-pyrimidine, 1,3-benzothiazole-2-thiol,4-amino-N-1,3-thiazol-2-ylbenzenesulfonamide, thiourea, guanidine,3,4-dimethylpyrazole phosphate,2,4-diamino-6-trichloromethyl-5-triazine, polyetherionophores,4-amino-1,2,4-triazole, 3-mercapto-1,2,4-triazole, potassium azide,carbon bisulfide, sodium trithiocarbonate, ammonium dithiocarbamate,2,3, dihydro-2,2-dimethyl-7-benzofuranol methyl-carbamate,N-(2,6-dimethylphenyl)-N-(methoxyacetyl)-alanine methyl ester, ammoniumthiosulfate, 1-hydroxypyrazole, 2-methylpyrazole-1-carboxamide,derivatives thereof, and any combination thereof. In at least oneexample, the nitrification inhibitor can be or include dicyandiamide(DCD). For example, 1-hydroxypyrazole can be considered a derivative of2-methylpyrazole-1-carboxamide and ammonium dithiocarbamate can beconsidered a derivative of methyl-carbamate.

As used herein, the term “urease inhibitor” refers to any compound(s)that reduces, inhibits, or otherwise slows down the conversion of ureato ammonium (NH₄ ⁺) in soil. Illustrative urease inhibitors can include,but are not limited to, N-(n-butyl)thiophosphoric triamide,N-(n-butyl)phosphoric triamide, thiophosphoryl triamide, phenylphosphorodiamidate, cyclohexyl phosphoric triamide, cyclohexylthiophosphoric triamide, phosphoric triamide, hydroquinone,p-benzoquinone, hexamidocyclotriphosphazene, thiopyridines,thiopyrimidines, thiopyridine-N-oxides, N,N-dihalo-2-imidazolidinone,N-halo-2-oxazolidinone, derivatives thereof, or any combination thereof.In at least one example, the urease inhibitor can be or includeN-(n-butyl)thiophosphoric triamide (NBPT).

The formaldehyde can be used in many forms. For example, paraform(solid, polymerized formaldehyde) and/or formalin solutions (aqueoussolutions of formaldehyde, sometimes with methanol, in about 10 wt %,about 20 wt. %, about 37 wt. %, about 44 wt. %, or about 50 wt. %, basedon the weight of the formalin solution) are commonly used forms. Forexample, the formaldehyde can be an aqueous solution having aconcentration of formaldehyde ranging from about 10 wt. % to about 50wt. %, based on a total weight of the aqueous solution. Formaldehyde gascan also be used. Formaldehyde substituted in part or in whole withsubstituted aldehydes such as acetaldehyde and/or propylaldehyde can beused as the source of formaldehyde. One or more other aldehydes, such asglyoxal can be used in place of or in combination with formaldehyde. Anyof these forms of formaldehyde sources can be used alone or in anycombination to prepare the reaction product.

The urea can also be used in many forms. For example, the urea can be asolid in the form of prills, flakes, granules, and the like, and/or asolution, such as an aqueous solution. Further, the urea may be combinedwith another moiety, for example, formaldehyde and/or urea-formaldehydeadducts, often in aqueous solution. As noted above, the nitrogen sourcecan be or include animal waste such as urine and/or manure. As such, atleast a portion of the urea, if present, can be in the form of animalwaste. Any form of urea or urea in combination with formaldehyde can beused to make a urea-formaldehyde polymer. Both urea prill and combinedurea-formaldehyde products can be used. Illustrative urea-formaldehydeproducts can include, but are not limited to, Urea-FormaldehydeConcentrate (“UFC”). These types of products can be as discussed anddescribed in U.S. Pat. Nos. 5,362,842 and 5,389,716, for example. Any ofthese urea sources can be used alone or in any combination to preparethe reaction product.

As used herein, the term “ammonia source” refers to ammonia or anyammonium compound(s) that liberate ammonia when reacted with theformaldehyde and the nitrification inhibitor. Illustrative ammoniasources can include, but are not limited to, ammonium salts such asammonium nitrate, aqueous ammonia or ammonium hydroxide, anhydrousammonia, or combinations thereof. Suitable aqueous ammonium solutionscan have an ammonia concentration of about 28 wt. %, about 30 wt. %,about 32 wt. %, or about 35 wt. %, for example. Other suitable ammoniasources can include, but are not limited to, primary amines orsubstituted primary amines such as methyl amine, monomethanol amine,amino propanol, or any combination thereof. Difunctional amines such asethylene diamine or any combination of organic amines provided that oneprimary amine group is available to form a triazone ring can be used.Another source of ammonia can be in the form of animal waste such asurine and/or manure. Any of these ammonia sources can be used alone orin any combination to prepare the reaction product. And the ammoniasource can be used in any form such a liquid, solid, and/or gas. In someembodiments, a specific ammonia source may be expressly excludedaccording to the present disclosure. For example, as further describedherein, an ammonia source may expressly exclude the use of ammoniumchloride. Other ammonia sources may be excluded if such ammonia sourcehas a pH in water of less than 7 and/or if such ammonia source providesan undesirable reduction in the pH of a reaction as described herein forforming adducts.

In some embodiments, the present disclosure can relate to adducts formedin the reaction of urea (see Formula 1), formaldehyde (see Formula 2),DCD (see Formula 3), and ammonia (NH₃). Such adducts are describedherein as being representative of the scope of compounds andcompositions encompassed by the present disclosure. It is understoodthat adducts likewise may be formed utilizing nitrification inhibitorsin addition to DCD.

Adducts arising from the reaction of urea, formaldehyde, DCD, andammonia may be encompassed by the structure of Formula 4

wherein:

X is O or

R₁, R₂, R₃, and R₄ are independently selected from the group consistingof:

and

wherein, if X═O,

at least one of R₁, R₂, R₃, and R₄ is

The reaction of materials as described herein may result in theformation of a plurality of different adducts. For example, a reactionproduct according to the present disclosure may include at least 1adduct, at least 2 different adducts, at least 3 different adducts, atleast 4 different adducts, at least 5 different adducts, at least 10different adducts, at least 25 different adducts, at least 50 differentadducts, or at least 100 different adducts. The adducts may be in theform of discrete compounds, oligomers, polymers, and combinationsthereof. The adducts may have a weight average molecular weight (ormolar mass) of about 100 Da or greater. Molar mass of the adducts may beabout 100 Da to about 10,000 Da, about 100 Da to about 5,000 Da, about100 Da to about 1,000 Da, or about 100 Da to about 500 Da. In someembodiments, a set of adducts arising from a single reaction utilizingmaterials as described herein may include adducts falling within 2 ormore, 3 or more, 4 or more, or 5 or more different ranges. For example,molar mass ranges may be characterized as being: between 100 Da and 200Da; between 200 Da and 300 Da; between 300 Da and 400 Da; between 500 Daand 1,000 Da, between 1,000 Da and 2,000 Da; and 2,000 Da and greater. Aset of adducts arising from the reaction of materials as describedherein may include adducts with a molar mass falling within at least twoof the foregoing ranges, at least three of the foregoing ranges, or atleast four of the foregoing ranges.

Beneficially, the nature of the several adducts that may be present in asingle set of reaction products may be envisioned based upon thematerials utilized in the reaction. For example, in the reaction ofurea, formaldehyde, DCD, and ammonia, adducts arising therefrom would berecognizable as falling within the structure of Formula 4 as describedabove. Substitution of a reactant would be expected to lead to formationof adducts of similar structure but including conserved substituentgroups from the substituted reactant. For example, in embodimentswherein DCD may be replaced with a different nitrification inhibitor,formed adducts would be expected to have a group of structures similarto that described by Formula 4, but the active groups from the differentnitrification inhibitor would be expected to replace the cyanamide groupfrom the DCD. Thus, the exemplary adducts arising from the reaction ofurea, formaldehyde, DCD, and ammonia can provide a basis whereby theadducts formed by the reaction of different materials may be envisioned,particularly in embodiments wherein urea (or a urea source) andformaldehyde are utilized as reactants.

Specific adducts arising from the reaction of the various materials asdescribed herein can be identified by analytical methods, such as highperformance liquid chromatography (HPLC), liquid chromatography massspectrometry (LCMS), and nuclear magnetic resonance (NMR) spectroscopy.The types of adducts arising from a reaction according to the presentdisclosure can vary based upon the materials utilized in the reaction.For example, in embodiments encompassing the reaction of urea,formaldehyde, DCD, and ammonia, the reaction products may includeadducts selected from the group consisting of ureaformaldehyde (UF)oligomer adducts, DCD-formaldehyde oligomer adducts,urea-formaldehyde-DCD adducts, triazonyl-formaldehyde-DCD adducts, andcombinations thereof. As non-limiting examples, three specific adductsidentified by LCMS arising from the reaction of urea, formaldehyde, DCD,and ammonia are provided in Formula 5[2-cyano-1-((4-oxo-1,3,5-triazinan-1-yl)methyl)guanidine—molar mass of197.0], Formula 6 [1-((2-cyanoguanidino)methyl)urea—molar mass 156.0],and Formula 7 [2-cyano-1-((2-cyanoguanidino)methyl)guanidine—molar mass180.0]. Testing carried out confirming the formation of such reactionproducts is described in the appended Examples.

In some embodiments, a reaction product according to the presentdisclosure can include one, two, or all three of the adducts shown inFormulas 5 through 7 in any combination. In particular, a reactionproduct may include one or more of an adduct having a molecular weightof 197.0 Da, an adduct having a molecular weight of 156.0 Da, and anadduct having a molecular weight of 180.0 Da, such molecular weightsbeing confirmed by mass spectra.

The adducts defined in Formula 5, Formula 6, and Formula 7 arenon-limiting examples of reaction products as defined by the class ofadducts in Formula 4. Adducts that may be formed according to thepresent disclosure may include any combination of groups encompassed byR₁-R₄ in any number.

In some embodiments, the adducts according to this disclosure can have apolymeric backbone defined by Formula 8, wherein z is an integer of 1 orgreater, preferably 1 to 100.

N—C—N_(z)  (Formula 8)

Adducts having a backbone structure according to Formula 8 can bedefined according to the following:

-   -   at least one carbon in the backbone is substituted with the        group

-   -   at least one carbon in the backbone is optionally substituted        with the group ═O; and each nitrogen in the backbone        independently includes a substituent selected from the group        consisting of:

A further, non-limiting example of a urea-formaldehyde-DCD adduct thatmay arise from the reaction of urea, formaldehyde, DCD, and ammonia isshown in Formula 9. As seen therein, the —N—C—N— backbone is present inthe adduct.

Preparation of the Reaction Product

Reactions carried out for production of adducts as described herein canbe carried out by reacting a nitrification inhibitor with the furtherstarting components under conditions that preferentially conserves thenitrification inhibitor. Although starting components such as DCD, anammonia source, and formaldehyde may be reacted under acidic conditions,adducts as described herein would not expected to form under suchconditions because of a lack of conservation of the DCD cyanamide group.For example, the reaction of ammonium chloride, formaldehyde, and DCDleads to UF condensation at a pH of approximately 5-5.2 in light of theproduction of HCl from the reaction of the ammonium chloride and theformaldehyde. Under such conditions, substantially all of the DCDprovided as a reactant is converted to a UF-guanidine product due to thecyano functional groups of the DCD being hydrolyzed. As such, theresulting reaction product is substantially lacking in any nitrificationinhibiting function because of the absence of unreacted DCD or reactionproducts incorporating the DCD cyanamide group. Such result would beexpected to occur under similar reaction conditions where an acidcatalyst (e.g., ammonium chloride) is utilized.

Preferably, adducts according to the present disclosure can be producedunder basic or alkaline reaction conditions. For example, adducts can beformed by reacting a nitrification inhibitor, a urea source,formaldehyde, and an ammonia source (preferably one that does not forman acid moiety during the reaction) under basic reaction conditions at apH of greater than 7. For example, the basic reaction conditions can beat a pH ranging from a low of about 7, about 7.5, about 8, about 8.5, orabout 9 to a high of about 9.5, about 10, about 10.5, or about 11.

The reaction product produced under basic reaction conditions can beprepared by combining, mixing, or otherwise contacting the reactioncomponents to produce a reaction mixture having a pH greater than about7. For example, a reaction mixture of formaldehyde, ammonia, anitrification inhibitor, and urea under the basic reaction conditionscan have a pH ranging from a low of about 8, about 8.5, or about 9 to ahigh of about 9.5, about 10, about 10.5, or about 11. Similarly, thereaction mixture under the basic reaction conditions can also have a pHranging from a low of about 8, about 8.5, or about 9 to a high of about9.5, about 10, about 10.5, or about 11. Heat from the exothermicreaction can be allowed to heat the reaction mixture to a temperatureranging from a low of about 50° C., about 60° C., or about 65° C. to ahigh of about 80° C., about 90° C., or about 100° C. The reactionmixture can be maintained at an elevated temperature, e.g., about 50° C.to about 90° C. for a time ranging from about 1 minute to about 3 hours.The resulting reaction mixture can then be cooled to, for example, roomtemperature, to provide the reaction product, which can include one ormore adducts as described herein.

In another example, formaldehyde and a first portion of the ammoniasource can be combined to form a first mixture. The first mixture can beat least partially reacted, and the formaldehyde and ammonia may bepresent in the first mixture at a mole ratio of about 40:1, to about5:1, about 35:1 to about 10:1, or about 30:1 to about 15:1. Thenitrification inhibitor can then be added to the first mixture or to theat least partially reacted first mixture to produce a second mixture.The second mixture can be at least partially reacted, and thenitrification inhibitor and formaldehyde can be present in the secondmixture at a mole ratio of about 0.01:1 to about 2:1, about 0.05:1 toabout 1:1, or about 0.1:1 to about 0.5:1. Urea can then be added to thesecond mixture or the at least partially reacted second mixture toproduce a third mixture. The third mixture can be at least partiallyreacted, and the urea and formaldehyde can be present in the thirdmixture at a mole ratio of about 0.1:1 to about 5:1, about 0.25:1 toabout 2:1, or about 0.5:1 to about 1:1. A second portion of the ammoniasource can be added to the third mixture to produce a fourth mixture.The fourth mixture can be at least partially reacted to produce thereaction product of formaldehyde, urea, ammonia, and the nitrificationinhibitor. The temperature of the first mixture, second mixture, andthird mixture can be maintained at a temperature ranging from about 25°C. to about 70° C. The temperature of the fourth mixture can range fromabout 60° C. to about 90° C. and can be held at the increasedtemperature for a period of time ranging from about 5 minutes to about 3hours. As a non-limiting example of a reaction product, the mole ratioof formaldehyde:urea:DCD:ammonia in a reaction product according to someembodiments of this disclosure can be about 1:0.88:0.14:0.24.

The addition of the urease inhibitor, if present, can similarly becombined in any order or sequence to produce another reaction mixture orcan be combined with the first, second, third, and/or fourth reactionmixture. In another example, the reaction components can besimultaneously combined together to from a single reaction mixture. Inyet another example, the formaldehyde, the nitrification inhibitor, andthe urea can be combined to provide a first mixture and the ammoniasource can then be added to the first mixture to produce a secondmixture. The second mixture can then be reacted to produce the reactionproduct.

Exothermic heat generated from the first mixture, second mixture, thirdmixture, fourth mixture, or any number of mixtures, can be used, atleast in part, as the heat source for heating any one or more of thereaction mixtures. In another example, heat can be introduced to any oneor more of the reaction mixtures to provide a heated reaction mixturevia a heating coil or other heat exchanging device or system. Thetemperature of the reaction mixtures can be maintained below a desiredmaximum temperature, e.g., 100° C., via a cooling coil or other heatexchanging device or system.

One or more bases or base compounds can be added before and/or duringthe reaction to any one or more of the reaction mixtures and/or thereaction product to maintain and/or adjust the pH thereof. For example,the reaction product produced under basic reaction conditions can bemaintained at a pH of about 8 to about 11 during the reaction and/or forthe final reaction product. Illustrative base compounds suitable foradjusting the pH of the reaction product can include, but are notlimited to, ammonia, amines, e.g., primary, secondary, and tertiaryamines and polyamines, sodium hydroxide (NaOH), potassium hydroxide(KOH), or any combination thereof. An aqueous base solution can have anyconcentration. For example, an aqueous base solution of sodiumhydroxide, potassium hydroxide, or a combination thereof, having aconcentration ranging from a low of about 5 wt. %, about 10 wt. %, orabout 15 wt. % to a high of about 25 wt. %, about 50 wt. %, or about 75wt. % can be introduced to one or more of the reaction mixtures and/orthe reaction product in order to adjust and/or maintain the pH betweenabout 8 and about 11.

In another example, one or more pH buffering compounds, which can bufferthe pH of the reaction mixture(s) at a desired pH, can be added at thestart of the reaction. Illustrative pH buffering compounds can include,but are not limited to, triethanolamine, sodium borate, potassiumbicarbonate, sodium carbonate, potassium carbonate, or any combinationthereof. In another example the one or more pH buffering compounds canbe used in conjunction with one or more base compounds to adjust and/ormaintain a desired pH of the reaction mixture(s).

The reaction product produced under the basic reaction conditions canhave a pH greater than 7. For example, the reaction product offormaldehyde, the ammonia source, the nitrification inhibitor, and ureaproduced under the basic reaction conditions can have a pH ranging froma low of about 8, about 8.5, or about 9 to a high of about 9.5, about10, about 10.5, or about 11.

Additional details for reacting formaldehyde, urea, and an ammoniasource under basic conditions are discussed and described in U.S. Pat.Nos. 6,632,262 and 7,513,928 and U.S. Patent Application Publication No.2006/0196241, the disclosures of which are incorporated herein byreference.

The reaction product produced as described herein can include one ormore other additives. For example, ethylene diamine can be added to thereaction product and/or to an intermediate mixture formed during theproduction thereof. Ethylene diamine can help adjust, control, and/ormaintain water solubility of the reaction product. Other chelatingagents include ethylenediaminetetraacetic acid (EDTA),diethylenetriaminepentaacetic acid (DPTA),N(hydroxyethyl)ethylenediaminetriacetic acid (HEDTA), nitrilotriaceticacid (NTA), along with a wide range of conjugate bases for thepreviously listed acids. Suitable commercially available suspensionadditives can include, for example, K-Tionic, which is manufactured anddistributed by GBS Biosciences, LLC.

The reaction product from the reaction of formaldehyde, urea, theammonia source, and the nitrification inhibitor can include from about25 mol % to about 65 mol % formaldehyde, from about 10 mol % to about 25mol % urea, from about 5 mol % to about 25 mol % ammonia, and from about5 mol % to about 25 mol % nitrification inhibitor, based on the totalweight of the formaldehyde, urea, ammonia, and nitrification inhibitor.The formaldehyde can be present in an amount ranging from a low of about25 mol %, about 30 mol %, or about 35 mol % to a high of about 50 mol %,about 55 mol %, or about 60 mol %, based on the total weight of theformaldehyde, urea, ammonia, and nitrification inhibitor. The urea canbe present in an amount ranging from a low of about 12 mol %, about 14mol %, or about 16 mol % to a high of about 18 mol %, about 22 mol %, orabout 25 mol %, based on the total weight of the formaldehyde, urea,ammonia, and nitrification inhibitor. The ammonia can be present in anamount ranging from a low of about 7 mol %, about 9 mol %, or about 12mol % to a high of about 18 mol %, about 22 mol %, or about 25 mol %,based on the total weight of the formaldehyde, urea, ammonia, andnitrification inhibitor. The nitrification inhibitor can be present inan amount ranging from a low of about 7 mol %, about 9 mol %, or about12 mol % to a high of about 18 mol %, about 22 mol %, or about 25 mol %,based on the total weight of the formaldehyde, urea, ammonia, andnitrification inhibitor.

The reaction product of formaldehyde, the ammonia source, and thenitrification inhibitor can have a molar ratio of formaldehyde toammonia ranging from about 1:1 to about 8:1, about 2:1 to about 6:1,about 2.5:1 to about 5:1, about 3:1 to about 4:1, or about 2:1 to about4:1. The reaction product of formaldehyde, urea, the ammonia source, andthe nitrification inhibitor can have a molar ratio of formaldehyde toammonia ranging from about 1:1 to about 8:1, about 2:1 to about 6:1,about 3:1 to about 5:1, or about 3.5:1 to about 4.5:1. The reactionproduct of formaldehyde, urea, the ammonia source, the nitrificationinhibitor, and the urease inhibitor can have a molar ratio offormaldehyde to ammonia ranging from about 1:1 to about 8:1, about 2:1to about 6:1, about 3:1 to about 5:1, or about 3.5:1 to about 4.5:1.

The reaction product of formaldehyde, the ammonia source, and thenitrification inhibitor can have a molar ratio of formaldehyde tonitrification inhibitor ranging from about 1:1 to about 7:1, about 1.5:1to about 6.5:1, about 2:1 to about 6:1, about 2.5:1 to about 5:1, about2:1 to about 4:1, or about 2.5:1 to about 3.5:1. The reaction product offormaldehyde, urea, the ammonia source, and the nitrification inhibitorcan have a molar ratio of formaldehyde to nitrification inhibitorranging from about 1:1 to about 8:1, about 1:1 to about 7:1, about 2:1to about 8:1, about 3:1 to about 7.5:1, or about 3.5:1 to about 7:1.

The reaction product of formaldehyde, the ammonia source, thenitrification inhibitor, and the urease inhibitor can have a molar ratioof formaldehyde to nitrification inhibitor ranging from about 1:1 toabout 7:1, about 1:1 to about 5:1, about 1.5:1 to about 4:1, about 2:1to about 4:1, about 2.5:1 to about 3.5:1, or about 2.7:1 to about 3.5:1.The molar ratio of formaldehyde to the urease inhibitor in the reactionproduct of formaldehyde, the ammonia source, the nitrificationinhibitor, and the urease inhibitor can be the same or similar to themolar ratio of formaldehyde to the nitrification inhibitor.

The reaction product of formaldehyde, urea, the ammonia source, and thenitrification inhibitor can have a molar ratio of formaldehyde to urearanging from about 1:1 to about 4:1, about 1.1:1 to about 3.9:1, about1:1 to about 2:1, about 1:1 to about 1.5:1, or about 1:1 to about 1.3:1.The reaction product of formaldehyde, urea, the ammonia source, thenitrification inhibitor, and the urease inhibitor can have a molar ratioof formaldehyde to urea ranging from 1:1 to about 4:1, about 1.1:1 toabout 3.9:1, about 1:1 to about 2:1, about 1:1 to about 1.5:1, or about1:1 to about 1.3:1.

The reaction product can be produced by reacting formaldehyde, anammonia source, and a nitrification inhibitor. In another example, thereaction product can be produced by reacting formaldehyde, urea, anammonia source, and a nitrification inhibitor. In yet another example,the reaction product can be produced by reacting formaldehyde, anammonia source, a nitrification inhibitor, and a urease inhibitor. Instill another example, the reaction product can be produced by reactingformaldehyde, urea, an ammonia source, a nitrification inhibitor, and aurease inhibitor. In another example, the reaction product can beproduced by reacting formaldehyde, an ammonia source, and anitrification inhibitor mixed with a urease inhibitor. In still anotherexample, the reaction product can be produced by reacting formaldehyde,urea, an ammonia source, and a nitrification inhibitor mixed with aurease inhibitor. In other words, the urease inhibitor can be reactedinto the reaction product of formaldehyde, the ammonia source, thenitrification inhibitor, and optionally urea, mixed with the reactionproduct, or both.

In some embodiments, the present disclosure can relate to a compositionthat arises from the reaction of urea, formaldehyde, a nitrificationinhibitor (e.g., DCD), and ammonia. Such composition may becharacterized as a nitrification inhibitor system. The composition canbe a mixture of a plurality of materials, including reaction product(s)(i.e., adducts as described herein) and one or more unreacted startingcomponents. The composition particularly may be an aqueous mixtureincluding water. In some embodiments, the composition can comprise oneor more adducts as described herein admixed with one or more of: water;free DCD; ammonia, urea-formaldehyde polymer (UFP); and urea.

One or more adducts as described herein or a nitrification inhibitorsystem including one or more of such adducts can be mixed or otherwisecombined with one or more nitrogen sources to provide a fertilizerproduct. In some embodiments, a reaction mixture arising from thereaction of urea, formaldehyde, ammonia source, and nitrificationinhibitor can be used alone as a nitrogen fertilizer product.

The reaction product (i.e., one or more adducts as described herein or anitrification inhibitor system including one or more of such adducts)can be mixed, blended, or otherwise combined with the one or morenitrogen sources to form the fertilizer. For example, the reactionproduct can be mixed with the one or more nitrogen sources in a vesselor container to provide the fertilizer. Similarly, the one or morenitrogen sources can be mixed, blended, or otherwise combined with thereaction product to form the fertilizer. For example, the nitrogensource can be mixed with the reaction product in a vessel or containerto provide the fertilizer. The amount of the reaction product and theone or more nitrogen sources can vary, and the amount of the reactionproduct can be measured in terms of the amount of nitrogen contained inthe nitrogen source(s). For example, the amount of reaction product inthe fertilizer can range from about 0.1 wt. % to about 25 wt. %, basedon the total amount of nitrogen in the one or more nitrogen sources inthe fertilizer. In another example, the amount of reaction product inthe fertilizer can range from a low of about 0.5 wt. %, about 1 wt. %,about 2 wt. %, about 3 wt. %, about 4 wt. %, or about 5 wt. % to a highof about 10 wt. %, about 12 wt. %, about 15 wt. %, about 18 wt. %, about20 wt. %, or about 25 wt. %, based on the total amount of nitrogen inthe one or more nitrogen sources in the fertilizer. In another example,the amount of reaction product in the fertilizer can range from about0.5 wt. % to about 3 wt. %, about 5 wt. % to about 15 wt. %, about 8 wt.% to about 12 wt. %, or about 10 wt. % to about 20 wt. %, based on thetotal amount of nitrogen in the one or more nitrogen sources in thefertilizer.

In a specific example, a fertilizer product containing 907 kg (2,000lbs) of a urea ammonium nitrate solution containing 32 wt. % nitrogen(32% UAN) may contain 2.9 kg (6.4 lbs) or 1 wt. % of the reactionproduct, based on the total amount of nitrogen in the UAN solution. Inanother specific example, a fertilizer product containing 1,000 kg(2,200 lbs) of a 32% UAN solution may contain about 32 kg (70.5 lbs) or10 wt. % of the reaction product, based on the total amount of nitrogenin the UAN solution. In yet another specific example, a fertilizerproduct containing about 1,000 kg (2,200 lbs) of anhydrous ammonia,which has an 82 wt. % nitrogen content, may contain about 82 kg (181lbs) or about 10 wt. % of the reaction product, based on the totalamount of nitrogen in the anhydrous ammonia.

In another example, the nitrogen source can be mixed with the reactionproduct within the soil, on or about the surface of the soil, or acombination thereof. For example, the nitrogen source can be or includeanimal waste such as urine and/or manure deposited on and/or in thesoil. In another example, the nitrogen source can be or include afertilizer product previously applied to the soil. As such, the reactionproduct can be applied to the soil and mixed with the animal wasteand/or previously applied fertilizer(s) on the surface of and/or withinthe soil. The reaction product can be applied to the soil before,during, and/or after the animal waste and/or fertilizer(s) are depositedon/in the soil. In another example, the nitrogen source can be orinclude animal waste such as urine and/or manure that can be collectedand placed within a holding tank, pond, or the like, and the reactionproduct can be added to the animal waste to provide a mixture. Themixture can then be deposited about the soil to act as a fertilizertherein.

If the nitrogen source includes animal waste such as urine and/ormanure, the amount of the reaction product mixed or otherwise combinedwith the nitrogen source that includes the animal waste can range fromabout 0.1 wt. % to about 25 wt. %, based on the total amount of nitrogenin the one or more nitrogen sources. In another example, the amount ofreaction product mixed or otherwise combined with the nitrogen sourcethat includes the animal waste can range from a low of about 0.5 wt %,about 1 wt. %, about 2 wt. %, about 3 wt. %, about 4 wt. %, or about 5wt. % to a high of about 10 wt. %, about 12 wt. %, about 15 wt. %, about18 wt. %, about 20 wt. %, or about 25 wt. %, based on the total amountof nitrogen in the one or more nitrogen sources in the fertilizer. Inanother example, the amount of reaction product mixed or otherwisecombined with the nitrogen source that includes the animal waste canrange from about 0.5 wt. % to about 3 wt. %, about 5 wt. % to about 15wt. %, about 8 wt. % to about 12 wt. %, or about 10 wt. % to about 20wt. %, based on the total amount of nitrogen in the one or more nitrogensources in the fertilizer. In another example, in addition to or in lieuof animal waste as providing the nitrogen source, the nitrogen sourcecan be provided from one or more previous applications of a fertilizerthat contained urea, ammonia, ammonium nitrate, or any combinationthereof, for example. In other words, the reaction product can beapplied to a soil that contains a fertilizer containing urea, ammonia,ammonium nitrate, animal waste(s), or any combination thereof previouslyapplied thereto or a soil to which a fertilizer containing urea,ammonia, ammonium nitrate, animal waste(s), or any combination thereofmay be applied thereto.

In another example, the reaction product can be mixed or combined withone or more quick release nitrogen sources and one or more controlledrelease nitrogen sources to provide the fertilizer. For example, afertilizer product can include a mixture of the reaction product, aurea-formaldehyde polymer (UFP), and an aqueous solution of urea (U), anaqueous solution of ammonium nitrate (AN), an aqueous solution ofurea-ammonium nitrate (UAN), or any combination thereof. For example,the fertilizer product containing both quick release and controlledrelease nitrogen sources can include the controlled release nitrogensource(s) in an amount ranging from a low of about 10 wt. %, about 20wt. %, about 30 wt. %, or about 40 wt. % to a high of about 60 wt. %,about 70 wt. %, about 80 wt. %, about 90 wt. %, or about 95 wt. %, basedon the total weight of nitrogen in both the controlled release nitrogensource and the quick release nitrogen source. The fertilizer productcontaining both quick release and controlled release nitrogen sourcescan have a concentration of the reaction product ranging from about 0.5wt. % to about 25 wt. %, about 1 wt. % to about 15 wt. %, about 5 wt. %to about 20 wt. %, or about 1 wt. % to about 20 wt. %, based on thetotal nitrogen in the quick release nitrogen source(s). In anotherexample, the fertilizer product can include an aqueous urea-formaldehydesolution (UF) mixed with a quick release nitrogen source at a weightratio from about 90:10 to about 10:90, about 80:20 to about 20:80, about75:25 to about 25:75, or about 30:70 to about 70:30 and the reactionproduct can be present in an amount ranging from about 1 wt. % to about20 wt. % based on the total amount of nitrogen in the quick releasenitrogen source.

One or more fertilizer nutrient additives can be mixed or combined withthe reaction product and/or a reaction product and nitrogen sourcemixture. Illustrative fertilizer nutrient additives can include, but arenot limited to, phosphorous and/or potassium based nutrients. Acommercially available fertilizer nutrient can include, for example,K-Fol 0-40-53, which is a solution that contains 40 wt. % phosphate and53 wt. % potassium, which is manufactured and distributed by GBSBiosciences, LLC.

One or more pesticides, herbicides, fungicides, or any combinationthereof, can also be mixed or combined with the reaction product and/ora reaction product and nitrogen source mixture. Suitable pesticides,herbicides, and fungicides are well known.

Depending on the particular composition of the reaction product and/orthe particular composition of the fertilizer product containing thereaction product and one or more nitrogen sources application rates tosoil can widely vary. For example, a fertilizer product containing thereaction product and one or more nitrogen sources and having aconcentration of the reaction product ranging from about 0.5 wt. % toabout 25 wt. %, based on the total amount of nitrogen in the one or morenitrogen sources, can be applied to a soil in an amount ranging from alow of about 5 kg/hectare (kg/ha), about 10 kg/ha, about 20 kg/ha, about30 kg/ha, about 40 kg/ha, or about 50 kg/ha to a high of about 100kg/ha, about 150 kg/ha, about 200 kg/ha, about 250 kg/ha, about 300kg/ha, about 350 kg/ha, or about 400 kg/ha. In another example, thereaction product alone can be applied to a soil in an amount rangingfrom a low of about 1 kg/ha, about 3 kg/ha, about 5 kg/ha, about 7kg/ha, or about 10 kg/ha to a high of about 30 kg/ha, about 35 kg/ha,about 40 kg/ha, about 45 kg/ha, about 50 kg/ha, about 60 kg/ha, about 70kg/ha, or about 80 kg/ha. The particular amount of the reaction product,when applied alone to the soil, can be based, at least in part, on theamount of nitrogen within and/or on the soil and/or the amount ofnitrogen expected to be deposited on and/or within the soil.

Examples

In order to provide a better understanding of the foregoing discussion,the following non-limiting examples are offered. Although the examplesmay be directed to specific embodiments, they are not to be viewed aslimiting the invention in any specific respect. All parts, proportions,and percentages are by weight unless otherwise indicated.

Incubation Tests

Three reaction products (Ex. 1-3) mixed with a urea solution to producea liquid fertilizer solution were prepared and incubation tests wereconducted. A comparative example of a urea only solution, i.e., a ureasolution without a reaction product (C1), and a comparative example of aurea solution mixed with dicyandiamide (DCD) (C2) were also prepared andevaluated. For comparative example C2, the urea solution mixed with DCDwas not reacted. In other words, the DCD was mixed with the ureasolution to provide the fertilizer. A Control was also prepared thatconsisted of soil, i.e., no nitrogen source nor reaction product wasadded.

For Ex. 1, the reaction product was prepared according to the followingprocedure. In a reaction vessel, about 1,640 g of a 50 wt. % solution offormaldehyde was added at room temperature and the temperature wasincreased to 50° C. with a heating coil. Over a period of about 15minutes the temperature was reduced to 25° C. (about 1.7° C. per minute)with a cooling coil and 1,150 grams of DCD was added. The temperaturewas raised to 60° C. and then about 208 g of ammonium chloride wasslowly added in small amounts over a period of about 30 minutes. Theaddition of ammonium chloride caused an exothermic reaction to producethe reaction product. During the addition of the ammonium chloride thetemperature of the reaction product was allowed to increase to 80° C.and was held for about 10 minutes at 80° C. and then cooled to roomtemperature. The final fertilization additive had a pH of 5.1.

For Ex. 2, the reaction product was prepared according to the followingprocedure. In a reaction vessel, about 1,290 g of a 50 wt. % solution offormaldehyde was added at room temperature and the temperature wasincreased and maintained between 30° C. and 50° C. A first portion ofammonium hydroxide (60 g) was then added to the reaction vessel and thetemperature of the mixture was maintained below 60° C. About 260 g ofDCD was then added to the reaction vessel and the temperature of themixture was adjusted to between 35° C. and 50° C. About 1,378 g urea wasthen added to the reaction vessel. A second portion of ammoniumhydroxide (250 g) was then added to the reaction vessel. The temperatureof the reaction mixture was allowed to exothermically increase to about90° C. for less than 30 minutes and the temperature was reduced to 85°C. and held for 120 minutes. After heating the reaction mixture to 85°C., distillation was started and carried out until 416.1 g of distillatewas removed from the reaction mixture. A 25 wt. % solution of sodiumhydroxide was added throughout the reaction and distilled as needed toadjust the pH. The pH of the reaction mixture was kept above 8.4throughout the reaction. After distillation the reaction mixture wascooled down to provide the reaction product for Ex. 2. The reactionproduct for Ex. 2 had a final pH of 9.12.

For Ex. 3, the reaction product was prepared according to the followingprocedure. In a reaction vessel, about 555 g of a 50 wt. % solution offormaldehyde was added at room temperature. About 260 g of ammoniumhydroxide was then slowly added to the reaction vessel and thetemperature was allowed to exothermically increase to 80° C. About 186 gof DCD was then added to the reaction vessel and the temperature of thereaction mixture was maintained at 75° C. for about 20 minutes. Thereaction mixture was then cooled to produce the reaction product for Ex.3. A 25 wt. % solution of sodium hydroxide was added throughout thereaction as needed to adjust the pH. The pH of the reaction mixture waskept above 8.4 throughout the reaction. The reaction product for Ex. 3had a final pH of 7.81.

Incubation tests were performed using each Example 1-3 to evaluate thenitrogen transformations for each sample. The effect of each reactionproduct (Ex. 1-3) on the nitrogen concentration in the soil as bothammonium-nitrogen and nitrate-nitrogen were evaluated at three differentconcentrations of the reaction products. More particularly, theconcentration of DCD for a first set of samples was 0.75 wt. % (Table1), a second set of samples was 1.5 wt. % (Table 2), and a third set ofsamples was 3 wt. % (Table 3), where the weight percents of the DCDconcentration are based on the total weight of nitrogen in the ureasolution.

The soil used in the incubation tests was Greenville loamy soil(clay-loam, siliceous, thermic Plinthic Kandiudults). The soil had a pHof 6.76, an ammonium-nitrogen concentration of 1.3 ppm, and anitrate-nitrogen concentration of 2.4 ppm. The soil had a total nitrogenconcentration of 0.062 wt. % prior to adding any of the fertilizersolutions, an organic matter concentration of 1.14 wt. %, a CEC of 16.2cmol/kg, phosphorus concentration of 3.55 ppm, a sulfur concentration of3.5 ppm, and a zinc concentration of 0.11 ppm. The phosphorous andsulfur concentrations were determined according to the Bray-1 test. Thezinc concentration was determined according to the DTPA(diethylenetriaminepentaacetic acid) soil test.

Prior to introducing the fertilizer solutions, each soil sample wasincubated for 1 week at 24° C. and had an initial moisture at fieldcapacity. As used herein, the term “field capacity,” refers to thedrained upper limit or moisture content below which there is no freedrainage flow. During the one week incubation period the moisture wasreduced to about 80%. For each test 50 g of soil was placed into a cupand each cup was covered with a lid having four holes to allow foraeration and to minimize water loss.

Stock solutions containing each example were prepared by adding 2.15 gof urea and the corresponding amount of DCD (C2) or the reaction product(Ex. 1-3) to a 500 mL beaker to provide samples having 0.75 wt. % (Table1), 1.5 wt. % (Table 2), and 3 wt. % (Table 3) DCD based on the totalnitrogen concentration in the urea solution. After adding the urea (C1),urea plus DCD (C2), and urea plus the reaction products (Ex. 1-3), tothe beakers, the contents of each beaker were diluted to 500 mL withdistilled water to provide a stock solution. For the examples shown inTables 1-3 below, 5 mL of the corresponding stock solution wereintroduced via a pipette onto each 50 g soil sample and the cover wasplaced thereon. The amount of nitrogen contained in each example (Ex.1-3, C1, and C2) was 10 mg and the nitrogen was in the form of urea. Thesoil had at least an 80% field moisture capacity for each sample and ifneeded additional distilled water was used in order to achieve the 80%field moisture capacity.

Soil extractions were made at 1 week intervals to determine the amountof ammonium-nitrogen and nitrate-nitrogen in each example. A total of 10extractions were performed, namely at time=0 and after the 1^(st) week,2^(nd) week, 3^(rd) week, 4^(th) week, 5^(th) week, 6^(th) week, 7^(th)week, 8^(th) week, and the 10^(th) week. Extracting the nitrogen fromeach sample was done by adding 100 mL of a 2M potassium chloride (KCl)solution to each soil sample to be tested. The amount of nitrogen in theform of ammonium (NH₄ ⁺) and nitrate (NO₃) were then determined.

The amount of ammonium was determined using the well-known Berthelotreaction in which ammonia is chlorinated to monochloroamine, which thenreacts with salicylate to form 5-aminosalicylate. After oxidation andoxidative coupling, a green color complex was formed which was measuredat 660 nm using a spectrophotometer.

The determination of nitrate was determined based on the reduction ofnitrate (NO₃) to nitrogen dioxide (NO₂) by hydrazinium sulfate orcadmium metal. Then nitrite was determined by diazotizing withsulfanilamide and coupling with α-naphthylethylenediaminedihydrochloroide to form a colored azo dye which was measured at 540 nmwith a spectrophotometer.

Table 1 shows the results for samples that had 0.75 wt. % DCD (C2 andEx. 1-3) based on a total weight of nitrogen in the urea solution. Table2 shows the results for samples that had 1.5 wt. % DCD (C2 and Ex. 1-3)based on a total weight of nitrogen in the urea solution. Finally, Table3 shows the results for samples that had 3% wt. DCD (C2 and Ex. 1-3)based on a total weight of nitrogen in the urea solution.

TABLE 1 Urea Urea + Only DCD Ex. Ex. Ex. Control (C1) (C2) 1 2 3 Wk.Ammonium 0.16 0.39 0.38 0.37 0.43 0.35 0 (NH4⁺), mg N Nitrate (NO₃ ⁻),1.19 1.27 1.19 1.24 1.18 1.17 mg N Wk. Ammonium 0.13 6.81 8.08 7.40 7.658.07 1 (NH4⁺), mg N Nitrate (NO₃ ⁻), 1.22 3.61 2.39 3.22 2.89 2.36 mg NWk. Ammonium 0.02 4.21 6.95 5.21 5.55 6.42 2 (NH4⁺), mg N Nitrate (NO₃⁻), 1.27 6.37 3.50 5.35 5.08 4.02 mg N Wk. Ammonium 0.01 2.14 5.68 2.903.95 4.33 3 (NH4⁺), mg N Nitrate (NO₃ ⁻), 1.26 8.38 4.73 7.67 6.39 6.01mg N Wk. Ammonium 0.01 0.18 4.73 1.90 3.08 3.42 4 (NH4⁺), mg N Nitrate(NO₃ ⁻), 1.30 10.45 5.60 8.64 7.37 6.98 mg N Wk. Ammonium 0.07 0.08 1.680.43 1.37 1.43 5 (NH4⁺), mg N Nitrate (NO₃ ⁻), 1.35 10.69 8.92 10.259.40 9.14 mg N Wk. Ammonium 0.08 0.08 0.12 0.09 0.11 0.09 6 (NH4⁺), mg NNitrate (NO₃ ⁻), 1.48 10.66 10.50 10.69 10.93 10.77 mg N Wk. Ammonium0.09 0.09 0.11 0.11 0.10 0.11 7 (NH4⁺), mg N Nitrate (NO₃ ⁻), 1.31 10.8510.46 10.66 10.67 10.72 mg N Wk. Ammonium 0.09 0.10 0.11 0.09 0.08 0.098 (NH4⁺), mg N Nitrate (NO₃ ⁻), 1.40 10.97 10.76 10.88 10.98 10.73 mg NWk. Ammonium 0.03 0.04 0.06 0.05 0.05 0.05 10 (NH4⁺), mg N Nitrate (NO₃⁻), 1.46 10.98 10.86 10.84 11.22 10.82 mg N

As shown in Table 1, the urea and reaction product solutions (Ex. 1-3)having a nitrification inhibitor (DCD) concentration of 0.75 wt. % basedon the amount of nitrogen in the urea performed substantially betterthan the urea only solution (C1) and similarly to the urea+DCD solution(C2). For all the Examples 1-3 the amount of nitrogen in the form ofammonium (NH₄ ⁺) was substantially increased as compared to the ureaonly solution (C1) for weeks 3 through 5. At about the 6^(th) week theammonium (NH₄ ⁺) concentration for all examples dropped off. Similarly,for all the Examples 1-3 the amount of nitrogen in the form of nitrate(NO₃₎ was substantially less than the urea only solution (C1) for weeks3 through 5. At about the 6^(th) week the nitrate (NO₃) concentrationleveled off. The nitrification inhibition exhibited by Ex. 1-3 performedsimilarly to the urea+DCD solution (C2) in inhibiting the nitrificationprocess.

TABLE 2 1.5 wt. % DCD Based on the Weight of Nitrogen in the FertilizerUrea Urea + Only DCD Ex. Ex. Ex. Control (C1) (C2) 1 2 3 Wk. Ammonium0.16 0.39 0.38 0.28 0.27 0.36 0 (NH4⁺), mg N Nitrate (NO₃ ⁻), 1.19 1.271.20 1.18 1.24 1.28 mg N Wk. Ammonium 0.13 6.81 8.69 7.51 8.60 8.55 1(NH4⁺), mg N Nitrate (NO₃ ⁻), 1.22 3.61 1.86 2.76 2.17 1.91 mg N Wk.Ammonium 0.02 4.21 7.97 5.42 7.08 7.80 2 (NH4⁺), mg N Nitrate (NO₃ ⁻),1.27 6.37 2.44 5.03 3.40 2.50 mg N Wk. Ammonium 0.01 2.14 7.20 3.99 6.206.91 3 (NH4⁺), mg N Nitrate (NO₃ ⁻), 1.26 8.38 3.19 6.28 4.31 3.41 mg NWk. Ammonium 0.01 0.18 6.29 2.55 4.43 5.42 4 (NH4⁺), mg N Nitrate (NO₃⁻), 1.30 10.45 3.95 7.86 5.93 4.82 mg N Wk. Ammonium 0.07 0.08 4.23 1.463.67 3.61 5 (NH4⁺), mg N Nitrate (NO₃ ⁻), 1.35 10.69 6.20 9.02 6.95 6.92mg N Wk. Ammonium 0.08 0.08 1.24 0.10 0.54 0.96 6 (NH4⁺), mg N Nitrate(NO₃ ⁻), 1.48 10.66 9.10 10.61 10.15 9.25 mg N Wk. Ammonium 0.09 0.090.51 0.11 0.11 0.11 7 (NH4⁺), mg N Nitrate (NO₃ ⁻), 1.31 10.85 10.0210.54 10.94 10.25 mg N Wk. Ammonium 0.09 0.10 0.11 0.09 0.08 0.08 8(NH4⁺), mg N Nitrate (NO₃ ⁻), 1.40 10.97 10.68 10.92 11.01 10.50 mg NWk. Ammonium 0.03 0.04 0.05 0.04 0.04 0.04 10 (NH4⁺), mg N Nitrate (NO₃⁻), 1.46 10.98 10.63 10.74 10.85 10.61 mg N

As shown in Table 2, the urea and reaction product solutions (Ex. 1-3)having a nitrification inhibitor (DCD) concentration of 1.5 wt. % basedon the total amount of nitrogen in the urea solution performedsubstantially better than the urea only solution (C1) and similarly tothe urea+DCD solution (C2). For all the Examples 1-3 the amount ofnitrogen in the form of ammonium (NH4⁺) was substantially greater thanthe urea only solution (C1) for weeks 3 through 5. Ex. 2 and Ex. 3showed a substantial increase in the amount of nitrogen present in theform of ammonium (NH₄) through the 6^(th) week. Similarly, for all theExamples 1-3 the amount of nitrogen in the form of nitrate (NO₃ ⁻) wassubstantially less than the urea only solution (C1) for weeks 3 through5. Ex. 2 and Ex. 3 continued to show a substantial reduction in theconcentration of nitrogen in the form of nitrate (NO₃) through the6^(th) week. The nitrification inhibition exhibited by Ex. 1-3(especially Ex. 2 and 3) performed similarly to the urea+DCD solution(C2) in inhibiting the nitrification process.

TABLE 3 3 wt. % DCD Based on the Weight of Nitrogen in the FertilizerUrea Urea + Only DCD Ex. Ex. Ex. Control (C1) (C2) 1 2 3 Wk. Ammonium0.16 0.39 0.29 0.34 0.35 0.40 0 (NH4⁺), mg N Nitrate (NO₃ ⁻), 1.19 1.271.17 1.15 1.19 1.12 mg N Wk. Ammonium 0.13 6.81 8.74 8.06 9.05 9.01 1(NH4⁺), mg N Nitrate (NO₃ ⁻), 1.22 3.61 1.60 2.26 2.28 1.64 mg N Wk.Ammonium 0.02 4.21 8.20 7.13 8.55 8.28 2 (NH4⁺), mg N Nitrate (NO₃ ⁻),1.27 6.37 2.07 3.35 2.36 2.27 mg N Wk. Ammonium 0.01 2.14 7.53 6.36 7.807.63 3 (NH4⁺), mg N Nitrate (NO₃ ⁻), 1.26 8.38 2.78 4.07 3.10 2.96 mg NWk. Ammonium 0.01 0.18 6.05 4.08 6.20 5.83 4 (NH4⁺), mg N Nitrate (NO₃⁻), 1.30 10.45 4.10 6.22 4.56 4.49 mg N Wk. Ammonium 0.07 0.08 5.10 2.815.21 4.37 5 (NH4⁺), mg N Nitrate (NO₃ ⁻), 1.35 10.69 5.18 7.76 5.86 6.14mg N Wk. Ammonium 0.08 0.08 1.82 0.78 2.63 1.89 6 (NH4⁺), mg N Nitrate(NO₃ ⁻), 1.48 10.66 8.40 9.74 8.38 8.66 mg N Wk. Ammonium 0.09 0.09 0.610.11 0.41 0.12 7 (NH4⁺), mg N Nitrate (NO₃ ⁻), 1.31 10.85 9.58 10.4810.74 10.55 mg N Wk. Ammonium 0.09 0.10 0.20 0.09 0.41 0.11 8 (NH4⁺), mgN Nitrate (NO₃ ⁻), 1.40 10.97 10.35 10.73 10.91 10.74 mg N Wk. Ammonium0.03 0.04 0.05 0.04 0.04 0.04 10 (NH4⁺), mg N Nitrate (NO₃ ⁻), 1.4610.98 10.66 10.85 11.35 10.88 mg N

As shown in Table 3, the urea and reaction product solutions (Ex. 1-3)having a nitrification inhibitor (DCD) concentration of 3 wt. % based onthe total amount of nitrogen in the urea solution performedsubstantially better than the urea only solution (C1) and similarly tothe urea+DCD solution (C2). For all the Examples 1-3 the amount ofnitrogen in the form of ammonium (NH₄ ⁺) was substantially greater thanthe urea only solution (C1) for weeks 1 through 6. Ex. 2 showed asubstantial increase in the amount of nitrogen present in the form ofammonium (NH₄ ⁺) through the 8^(th) week. Similarly, for all theExamples 1-3 the amount of nitrogen in the form of nitrate (NO₃ ⁺) wassubstantially less than the urea only solution (C1) for weeks 1 through6. The nitrification inhibition exhibited by Ex. 1-3 (especially Ex. 2and 3) performed similarly to the urea+DCD solution (C2) in inhibitingthe nitrification process.

It has been surprisingly and unexpectedly discovered that a reactionproduct of the nitrification inhibitor with formaldehyde and an ammoniasource (Ex. 1 and Ex. 3) and a reaction product of the nitrificationinhibitor with formaldehyde, urea, and an ammonia source (Ex. 2) reducesthe rate at which nitrification of the nitrogen in the fertilizeroccurs. As shown in Tables 1-3, the reaction products of Examples 1-3showed a substantial decrease in the rate at which nitrificationoccurred in the urea only solution (C1) and performed similarly to theurea+DCD solution (C2).

Leaching Tests

One reaction product (Ex. 4) mixed with a urea solution to produce aliquid fertilizer solution was prepared and leaching tests wereconducted. In addition to Ex. 4, two comparative examples (C3 and C4)were also prepared. Comparative example C3 was a mixture of urea andDCD. Comparative example C4 was a mixture of urea ammonium nitrate(UAN), DCD, and a urea-formaldehyde polymer (UFP).

The reaction product used to produce the liquid fertilizer solution ofEx. 4 was the same reaction product used in Ex. 2. For Ex. 4 and C3, astock urea solution was prepared by dissolving 152.6 g urea in distilledwater and diluting to 1 L. 50 mL of the stock urea solution was thenadded to each of two 500 mL volumetric flasks. To prepare the fertilizersolution of Ex. 4, about 1,008.9 mg of the reaction product of Ex. 4 wasadded to the first volumetric flask and distilled water was added tobring the volume to 500 mL. To prepare the fertilizer solution ofcomparative example C3, about 106.2 mg of DCD was added to the secondvolumetric flask and distilled water was added to bring the volume to500 mL.

The urea-formaldehyde polymer (UFP) of comparative example C4 wasprepared according to the following procedure. In a reaction vessel,about 1,884 g of a 50% solution of formaldehyde was added at roomtemperature and the temperature was increased and maintained betweenabout 30° C. and about 50° C. A first portion of ammonium hydroxide(about 70 g) was then added to the reaction vessel and the temperatureof the mixture was maintained below about 60° C. About 942 grams of ureawas then added to the reaction vessel and the temperature of the mixturewas adjusted to between about 35° C. and about 50° C. A second portionof ammonium hydroxide (about 403 g) was then added to the reactionvessel. The temperature of the reaction mixture was allowed toexothermically increase to about 90° C. for less than 30 minutes and thetemperature was reduced to about 85° C. and held for about 120 minutesduring which time distillation was started and carried out until about921 g of distillate was removed form the reaction mixture. A 25 wt. %solution of sodium hydroxide was added throughout the reaction anddistillation as needed in order to maintain the pH of the reactionmixture above about 8.4 throughout the reaction. After distillation, thereaction mixture was cooled down to provide a reaction product of theurea-formaldehyde polymer (UFP), which had a final pH of about 10.2 anda nitrogen concentration of about 22 wt. % based on the weight of thereaction product.

A urea-formaldehyde polymer/urea ammonium nitrate (UFP/UAN) solution wasprepared by blending about 73.3 g of urea ammonium nitrate (UAN) havinga nitrogen concentration of about 32 wt. % with about 26.7 g of theurea-formaldehyde polymer (UFP) to produce an 80:20 blend where about80% of the nitrogen was in the UAN and about 20% of the nitrogen was infrom the UFP.

A final solution containing DCD and the UFP/UAN solution was thenprepared. About 12.2 g of the UAN/UFP solution (about 29.1% N) was thenadded to a 500 mL volumetric flask along with about 106.2 mg of DCD. Theflask was filled to 500 mL using distilled water. This UAN/UFP/DCDsolution was used as the fertilizer of comparative example C4.

Table 4 below summarizes the amount of each nitrification inhibitorincluded in Ex. 4, C3, and C4.

TABLE 4 Nitrification Inhibitor Amounts Percent Amount Inhib- Amountapplied Total Inhibitor itor added per column in Amount Exam- (wt. %Inhibitor/ to 500 mL 50 mL (mg of DCD ple wt. % Nitrogen) Flasks (mg)Inhibitor) (mg) Ex. 4 28.5 1,008.9 100.9 10.6 C3 3.0 106.2 10.6 10.6 C43.0 106.2 10.6 10.6

The leaching tests were conducted on two types of soil and each example(Ex. 4, C3, and C4) was replicated 3 times. As such, the total number ofleaching columns was equal to 3 nitrogen sources×2 types of soil×3replicates for a total of 18 leaching columns.

The first type of soil used in the leaching tests was Greenville clayloam soil (a fine, kaolinitic, thermic Rhodic Kandiudults) having thefollowing properties: a soil pH of about 6.82, an ammonium-Nconcentration of about 6.3 ppm, a nitrate-N concentration of about 3.1ppm, 0.060 wt. % total nitrogen, 1.14 wt. % organic matter, a cationexchange capacity (CEC) of about 16.2 cmol kg⁻¹, a phosphorousconcentration (Bray-1 P) of 3.55 ppm, a sulfur concentration of 3.5 ppm,and a diethylenetriaminepentaacetic acid-extractable zinc concentration(DTPA-Zn) of 0.11 ppm. The Greenville soil has optimum pH fornitrification, moderate texture and a low enough N content to show theeffect of added N fertilizer.

The second type of soil used in the leaching tests was Tifton sandy loamsoil (a fine-loamy, siliceous, thermic Plinthic Kandiudults) having thefollowing properties; a soil pH of about 4.90, about 1.15 wt. % organicmatter, an ammonium-N concentration of about 4.1 ppm, a nitrate-Nconcentration of about 9.0 ppm, about 0.038 wt. % total nitrogen, a CECof about 1.8 cmol kg⁻¹, and about 79 wt. % sand.

The leaching columns had an inner diameter of 15 cm, a height of 30 cm,and were kept at room temperature, i.e., between about 20° C. and 24° C.Each leaching column had the bottom 5 cm filled with about 800 g ofacid-washed sand and the rest of the column was uniformly filled withabout 6 kg of the appropriate soil. The sand was washed with 1 M HCl,rinsed with de-ionized water, and spread out to dry before being put inthe leaching columns.

The duration of the experiment was 10 weeks (2 weeks before fertilizerapplication plus a 7 week period of water addition plus final week ofdrying cycle). The soil used in the leaching columns had a soil moisturecontent at 50% of field capacity for three weeks before the start of theexperiment, i.e., before loading into the leaching columns. The twotypes of soil differed in field capacity moisture content—the Greenvillesoil had a field capacity moisture content of 24.5% and the Tifton soilhad field capacity moisture content of 11.52%.

The total amount of nitrogen (N) applied as either urea or UAN+UFP tothe soil in the leaching columns was equal to about 200 kg N/ha or about354 mg N/leaching column. In other words, the total amount of nitrogen(N) applied to each leaching column was equal to about 354 mg.

After application of the fertilizer/inhibitor (Ex. 4, C3, and C4), theleaching columns were maintained at about 80-90% field capacity moisturecontent for the first four days. On the fifth through the seventh days(days 5-7), each leaching column received 14 mm per day water (250 mLper day) delivered uniformly over the soil surface. The three days ofwater addition were followed by two dry days (days 8-9) to ensure soilmoisture in none of the leaching columns exceeded field capacity for aprolonged period of time. The three-day watering followed by two dry daycycles was repeated up to day 20. From then on a three-day wateringfollowed by four dry days was followed until the last water applicationon day 50. The last drying continued to the termination of theexperiment (on day 57).

Leachate from the Greenville clay loam soil was analyzed for DCD aboutevery two days. Table 5 shows the Mean Daily DCD concentration (ppm),Quantity Leached (mg DCD per day), DCD Recovery (percent of DCD added tosoil that was recovered in the leachate), and DCD in the Soil (percentof DCD that was not leached from the soil) for the Greenville clay loamsoil.

TABLE 5 DCD Analysis Results - Greenville Clay Loam Soil DCD Mean DCDMean DCD DCD that Daily Leach Daily Leach Recovered in Remained inExample (ppm) (mg) Leachate (%) Soil (%) Ex. 4 1.9 0.0067 15.4 84.6 C33.23 0.2830 61.4 38.6 C4 3.16 0.2760 59.8 40.2

As shown in Table 5, the fertilizer of Ex. 4, i.e., the mixture of ureaand the reaction product surprisingly and unexpectedly substantiallyoutperformed both the urea/DCD solution (C3) and the UAN/UFP/DCDsolution (C4) for inhibiting leaching of the DCD. The total DCD leachingloss for the urea and reaction product solution (Ex. 4) was 42 timeslower than the urea/DCD solution (C3) and 41 times lower than theUAN/UFP/DCD solution (C4). Said another way, the urea and reactionproduct solution (Ex. 4) maintained 84.6% of the DCD applied to the soilwithin the soil, while only 15.4% of the DCD leached out of the soil. Incontrast, the comparative examples C3 and C4 maintained only about 38.6%and about 40.2% of the DCD applied to the soil within the soil.Accordingly, Table 5 clearly shows that Ex. 4 performed substantiallysuperior to both comparative examples (C3 and C4) that had about 61.4%and about 59.8% of the DCD applied to the soil, respectively, leachedtherefrom.

Leachate from the Tifton sandy loam soil was also analyzed for DCD aboutevery two days. Table 6 shows the Mean Daily DCD concentration (ppm),Quantity Leached (mg DCD per day), DCD Recovery (percent of DCD added tosoil that was recovered in the leachate), and DCD in the Soil (percentof DCD that was not leached from the soil) for the Tifton sandy loamsoil.

TABLE 6 DCD Analysis Results - Tifton Sandy Loam Soil DCD Mean DCD MeanDCD DCD that Daily Leach Daily Leach Recovered in Remained in Example(ppm) (mg) Leachate (%) Soil (%) Ex. 4 1.94 0.0075 17.1 82.9 C3 3.110.2750 59.7 40.3 C4 3.34 0.3090 67.1 32.9

As shown in Table 6, the fertilizer of Ex. 4, i.e., the mixture of ureaand the reaction product surprisingly and unexpectedly substantiallyoutperformed both the urea/DCD solution (C3) and the UAN/UFP/DCDsolution (C4) for inhibiting leaching of the DCD. The total DCD leachingloss for the urea and reaction product solution (Ex. 4) was about 37times lower than the urea/DCD solution (C3) and about 41 times lowerthan the UAN/UFP/DCD solution (C4). Said another way, the urea andreaction product solution (Ex. 4) maintained about 82.9% of the DCDapplied to the soil within the soil, while only about 17.1% of the DCDleached out of the soil. In contrast, the comparative examples C3 and C4maintained only about 40.3% and about 32.9% of the DCD applied to thesoil within the soil. Accordingly, Table 6 clearly shows that Ex. 4performed substantially superior to both comparative examples (C3 andC4) that had about 59.7% and about 67.1% of the DCD applied to the soil,respectively, leached therefrom.

Not wishing to be bound by theory, it is believed that the reactionproducts produced by reacting the nitrification inhibitor withformaldehyde and an ammonia source (Ex. 1 and Ex. 3) or withformaldehyde, urea, and an ammonia source (Ex. 2) and (Ex. 4) willexhibit superior nitrification inhibition in real world applications ascompared to the nitrification inhibitor applied alone or simply mixedwith urea (U), ammonium nitrate (AN), and/or urea ammonium nitrate (UAN)because leaching of the nitrification inhibitor into the surroundingsoil and away from the nitrogen source in the fertilizer should bereduced or prevented. In other words, reacting the nitrificationinhibitor into a polymer should hold or maintain the presence of thenitrification inhibitor at the point of application, i.e., at the rootsof the plant, where the fertilizer, e.g., urea, ammonium nitrate, or amixture of urea and ammonium nitrate, is present, thus providing animproved nitrification inhibitor. As such, the nitrification inhibitorcan more effectively inhibit the loss of nitrogen from a nitrogen sourcethrough the process of nitrification because tendency for thenitrification inhibitor to leach into the soil and away from thefertilizer is reduced or inhibited.

Additionally, as shown in comparative example C4, simply mixing thenitrification inhibitor (DCD) with a urea-formaldehyde polymer insteadof reacting the nitrification inhibitor into the urea formaldehydepolymer (Ex. 1-4) did not decrease the amount of nitrification inhibitorleached from the soil. Indeed, there is no statistical differencebetween the two comparatives C3 and C4. Accordingly, incorporating thenitrification inhibitor into the reaction product can more effectivelyinhibit the loss of nitrogen from a nitrogen source through the processof nitrification because tendency for the nitrification inhibitor toleach into the soil and away from the fertilizer is reduced orinhibited.

Also, not wishing to be bound by theory, it is believed that applying areaction product produced by reacting formaldehyde, an ammonia source,and a nitrification inhibitor, and optionally urea and/or a ureaseinhibitor to soil or other substrates that already contains or may beexpected to contain one or more nitrogen sources can reduce or preventthe loss of at least one of the one or more nitrogen sources through theprocess of nitrification because the tendency for the nitrificationinhibitor to leach into the soil and away from the fertilizer is reducedor inhibited. As such, the reaction product can be applied to a soilthat contains or may be expected to contain nitrogen sources such asthose introduced to soil from one or more animals via manure and/orurine and/or previous fertilizer applications and the loss of thenitrogen source(s) through nitrification can be reduced or prevented.

Structural Analysis of Reaction Products

Reaction product compositions were prepared via a basic reaction asdescribed herein using formaldehyde, DCD, urea, and ammonia asreactants. The reaction product compositions were subjected to LCMSspectral analysis along with a comparative sample of NITAMIN® 30L, whichis urea-formaldehyde fertilizer composition of known composition. Thespectral graphs were obtained using an Agilent 6330 Ion Trap LCMS with aGrace Adsorbosphere NH₂ 3 μm 150 mm×4.6 mm column and a 214 nm UVdetector. Samples consisted of approximately 0.03 grams of reactionproduct in 10 mL of 90:10 acetonitrile/water. A sample injection volumeof 2 μL was used with the device operating with a flow rate of 1.0mL/min at a temperature of 30° C. Sample run time was 25 minutes. Themobile phase was a mixture of 95% acetonitrile and 5% water by weight.An isocratic aqueous normal phase separation was performed using an NH₂end-capped stationary phase.

Analysis confirmed the presence of a plurality of reaction productsincluding adducts as described herein. Fifteen peaks corresponding todifferent components in the reaction product were selected from theresulting UV and total ion chromatograms. The UV (214 nm) chromatogramshowing the fifteen peaks is provided in FIG. 1, and peak identificationis provided in Table 7 (wherein M represents the separate identifiedcompounds).

TABLE 7 LCMS Spectral Peak Identification Peak Number Compound Identityof Ionized Mass (±0.2 Da) 1 M + Na⁺ = 148.0 Da 2 DCD 3 Urea 4 M + Na⁺ =220.0 Da 5 Unknown/Appears in NITAMIN ® 30L 6 Unknown/Appears inNITAMIN ® 30L 7 M + Na⁺ = 179.0 Da 8 M + Na⁺ = 251.1 Da 9 M + Na⁺ =261.1 Da 10 M + Na⁺ = 244.1 Da 11 M + Na⁺ = 155.0 Da Appears inNITAMIN ® 30L 12 M + Na⁺ = 220.0 Da 13 M + Na⁺ = 292.1 Da 14 M + Na⁺ =220.0 Da 15 M + Na⁺ = 196.0 Da Appears in NITAMIN ® 30L

Mass spectral analysis confirmed that peak 4 corresponds to the adductof Formula 5, the recorded mass of 220.0 Da being the sum of the adductmass (197.0 Da) and the sodium ion mass (23.0 Da). See FIG. 2. Theanalysis further confirmed that peak 7 corresponds to the adduct ofFormula 6, the recorded mass of 179.0 Da being the sum of the adductmass (156.0 Da) and the sodium ion mass (23.0 Da). See FIG. 3.

Certain embodiments and features have been described using a set ofnumerical upper limits and a set of numerical lower limits. It should beappreciated that ranges from any lower limit to any upper limit arecontemplated unless otherwise indicated. Certain lower limits, upperlimits and ranges appear in one or more claims below. All numericalvalues are “about” or “approximately” the indicated value, and take intoaccount experimental error and variations that would be expected by aperson having ordinary skill in the art.

Various terms have been defined above. To the extent a term used in aclaim is not defined above, it should be given the broadest definitionpersons in the pertinent art have given that term as reflected in atleast one printed publication or issued patent. Furthermore, allpatents, test procedures, and other documents cited in this applicationare fully incorporated by reference to the extent such disclosure is notinconsistent with this application and for all jurisdictions in whichsuch incorporation is permitted.

While the foregoing is directed to embodiments of the present invention,other and further embodiments of the invention may be devised withoutdeparting from the basic scope thereof, and the scope thereof isdetermined by the claims that follow.

What is claimed is:
 1. A method of preparing a nitrification inhibitorsystem, the method comprising reacting formaldehyde, DCD, urea, and anammonia source so as to form an aqueous solution comprising aDCD-formaldehyde adduct.
 2. The method according to claim 1, wherein thereacting is at a pH of 7 or greater.
 3. The method according to claim 1,wherein the DCD adduct comprises one or both of atriazonyl-formaldehyde-DCD adduct and a urea-formaldehyde-DCD adduct. 4.The method according to claim 3, further comprising aDCD-formaldehyde-oligomer adduct.
 5. The method according to claim 1,wherein said reacting comprises reacting formaldehyde with at least aportion of the ammonia source to form a first mixture.
 6. The methodaccording to claim 5, wherein said reacting further comprises reactingthe first mixture with the DCD to form a second mixture.
 7. The methodaccording to claim 6, wherein said reacting further comprises reactingthe second mixture with urea to form a third mixture.
 8. The methodaccording to claim 7, wherein said reacting further comprises reactingthe third mixture with a portion of the ammonia source.
 9. The methodaccording to claim 1, wherein said DCD-formaldehyde adduct comprises atleast a structure according to Formula 4:

wherein: X is O or

R₁, R₂, R₃, and R₄ are independently selected from the group consistingof:

and wherein, if X═O, at least one of R₁, R₂, R₃, and R₄ is


10. The method according to claim 3, wherein thetriazonyl-formaldehyde-DCD adduct comprises at least a structureaccording to Formula 5:


11. The method according to claim 3, wherein the urea-formaldehyde-DCDadduct comprises at least a structure according to Formula 6:


12. The method according to claim 4, wherein theDCD-formaldehyde-oligomer adduct comprises at least a structureaccording to Formula 7: